Abstract: An amplifier and a method of outputting a waveform of a music signal capable of outputting a waveform of a music signal exceeding a power supply voltage is provided. An amplifier includes a power supply, an input terminal for a music signal, an amplifying circuit which amplifies the music signal using the power supply, and a jumping-up circuit which is connected to an output end of the amplifying circuit and outputs a waveform exceeding a voltage value of the power supply.

Abstract: A fully integrated power amplifier (PA) employing a transformer combiner with enhanced back-off efficiency includes a first PA to amplify a first radio frequency (RF) signal and a second PA to amplify a second RF signal. A first variable capacitor is coupled between differential output nodes of the first PA. A second variable capacitor is coupled between differential output nodes of the second PA. The differential outputs of the first PA and the second PA are coupled via respective first and second transformers to a load. Capacitance values associated with the first and second variable capacitors are dynamically adjustable based on an amplitude of the RF signal to achieve a desired power efficiency at an output power level.

Abstract: A transceiver includes: a power amplifying circuit arranged to generate differential output signals during a transmitting mode of the transceiver; a balance-unbalance circuit arranged to convert the differential output signals into a single-ended output signal; a switchable matching circuit arranged to receive the single-ended output signal on a signal port of the transceiver during the transmitting mode, and to convert a single-ended receiving signal on the signal port into a single-ended input signal during a receiving mode of the transceiver; and a low-noise amplifying circuit arranged to convert the single-ended input signal into a low-noise input signal during the receiving mode. The power amplifying circuit, the Balun, the switchable matching circuit, and the low-noise amplifying circuit are configured as a single chip.

Abstract: A system that includes an amplification circuit; a resonant circuit that is arranged to receive the amplified signal and to output an resonant circuit output signal; wherein the resonant circuit comprises a continually tuned variable capacitor; a transformer that is arranged to receive the resonant circuit output signal and to output a transformer output signal; a coupler that is arranged to sample the transformer output signal and a reflected signal and to output a first signal that represents the transformer output signal and a second signal that represents a reflected signal; a detector that is arranged to receive the first and second signals and to output an impedance indicative signal a control circuit that is arranged to generate the resonant circuit tuning signal in response to the impedance indicative signal and for compensating for the impedance mismatch.

Abstract: A power amplifier circuit, comprising: an amplifier for receiving an input signal to be amplified; a power input for coupling the amplifier to a power supply; and a transformer for providing the amplified signal from the amplifier to a load, comprising a primary inductor and a secondary inductor. The power amplifier circuit is characterized by: a first capacitor coupled in parallel with the primary inductor; and a second capacitor coupled in parallel with the secondary inductor; wherein at least one of the first and second capacitors has a variable capacitance.

Abstract: In one embodiment, the present invention includes a transformer formed on a semiconductor die. Such transformer may have multiple coils, including first and second coils. Each coil may have segments that in turn are formed on a corresponding metal layer of the semiconductor die. The segments of a given coil are coupled to each other, and the first and second coils can be interdigitated with each other.

Abstract: A power amplifier circuit, comprising: an amplifier for receiving an input signal to be amplified; a power input for coupling the amplifier to a power supply; and a transformer for providing the amplified signal from the amplifier to a load, comprising a primary inductor and a secondary inductor. The power amplifier circuit is characterized by: a first capacitor coupled in parallel with the primary inductor; and a second capacitor coupled in parallel with the secondary inductor; wherein at least one of the first and second capacitors has a variable capacitance.

Abstract: Embodiments for at least one method and apparatus of a multi-use voltage regulator providing a supply voltage to a power amplifier and at least one other device are disclosed. One method includes generating a plurality of regulated voltage supplies from an unregulated voltage. An output signal power level of the power amplifier is determined. A one of the regulated plurality of voltage supplies and the unregulated voltage supply is selected as a power amplifier voltage supply for the power amplifier based at least in part on the output signal power level of the power amplifier. If the selected power amplifier voltage supply is one of the plurality of regulated voltage supplies, then the selected one of the plurality of regulated voltage supplies is simultaneously provided to the power amplifier and the at least one other device.

Abstract: A power amplifier (PA) adjustably operable between two classes of operation. The range of operation lies in a range of operation between a conventional, linear, conjugately matched Class AB characteristic amplifier and a higher efficiency switching Class E characteristic amplifier. A circuit topology having a push-pull configuration that allows a Class E characteristic of operation.

Abstract: An on-chip power amplifier includes first and second variable capacitors connected in parallel with first and second windings, respectively, of an on-chip balun. The first balun winding connects between the differential outputs of an on-chip differential amplifier. Varying the first variable capacitor changes the imaginary part of the load impedance of the differential amplifier, while varying the second variable capacitor changes the real part of the load impedance of the differential amplifier. In one embodiment, the first and second variable capacitors are generally orthogonal, such that the first and second variable capacitors are less than 25% correlated. As a result, varying the first variable capacitor has little impact on the real part of the load impedance, and varying the second variable capacitor has little impact on the imaginary part of the load impedance. In this way the load impedance can be tuned to the optimum performance.

Abstract: A power amplifier (PA) adjustably operable between two classes of operation. The range of operation lies in a range of operation between a conventional, linear, conjugately matched Class AB characteristic amplifier and a higher efficiency switching Class E characteristic amplifier. A circuit topology having a push-pull configuration that allows a Class E characteristic of operation.

Abstract: Systems and methods are provided for a transformer or balun function with reference enhancement. The systems and methods may include a transformer having at least a primary winding and a secondary winding for reference enhancement, where the primary winding includes a center tap, where the secondary winding includes a first port and a second port, and an electrical connection that electrically connects the second port and the center tap of the primary winding to provide a common reference for the primary winding and the secondary winding. The primary winding of the transformer may be configured to receive differential outputs of a power amplifier, and the transformer may be configured to convert the differential outputs from a balanced signal to an unbalanced signal available at the first port of the secondary winding.

Abstract: A dual mode power amplifier output network is provided that includes a load switch and an auto transformer having a primary winding and a secondary winding. The load switch is connected to the secondary winding of the auto transformer.

Abstract: A signal coupler includes a transformer having a primary and a secondary winding. Each transformer winding has a pair of associated winding terminals and is also split at an intermediate winding position to form a pair of supplemental winding terminals. Circuitry is provided between each pair of supplemental winding terminals so as to provide different impedances in different frequency bands. In particular, a first circuit, which provides a first impedance in a first frequency range, is connected across the supplemental winding terminals of one winding. A second circuit, is connected across the supplemental winding terminals of the other transformer winding. This second circuit, in combination with the first, provides a second impedance in a second frequency range. In the disclosed embodiment, the first circuit provides an impedance of 600 ohms in the voiceband frequency range. The second circuit in combination with the first provides an impedance of 100 ohms in a frequency range extending above 40 kHz.

Abstract: A single ended audio amplifier having at least two primary windings, not necessarily matched, in the primary of an output matching transformer: one for the amplifier final stage; and another winding to produce in the same core a magnetizing force equal and opposite for out-of-band currents. Primary among these is quiescent current, but subsonic anode current variations due to signal or drift of operational conditions may be cancelled as well. A sensor tracks the quiescent and subsonic currents of the output amplifier device. The sensor output is low-pass filtered to control a three terminal current regulator that drives the second coil to oppose the out-of-band anode currents in the first (signal) coil of output transformer primary.

Abstract: A transconductance amplifier circuit employs the known combination of a transconductance amplifier and a current comparator (with or without a ratio extender, preferably in the form of a two-stage current transformer) to compare the output current from the transconductance amplifier with that flowing through a reference resistor, both these currents having been derived from the same alternating input voltage. A current corresponding to the unbalanced ampere-turns in the current comparator is used to produce a feed-forward error signal that is used to modify the output of the transconductance amplifier. The invention is characterized by an output transformer that has coaxial inner and outer toroidal magnetic cores, and primary and correction windings outside the outer core. This primary winding receives the output current from the transconductance amplifier and the correction winding receives the error signal.

Abstract: A combining circuit for Class-E RF power amplifiers includes a transformer for each power amplifier to be combined, the respective secondaries of the transformers being connected in series to the RF load of the system. Each of the transformers further has a tertiary winding, with one end connected to a first common circuit node, and the other end being connected to a second common circuit node via an inductance. A switchable reactive network is connected to the second common circuit node, and in the event that one of the power amplifiers is removed from the circuit, such as due to failure thereof, the primary terminating impedance of the transformer connected thereto will become a high impedance, and by appropriate switching of the reactive network, in combination with the remaining circuit components, the matching impedance necessary to maintain optimum operation of the remaining power amplifiers is achieved, with a benign VSWR being presented to the remaining power amplifiers.

Abstract: A transformer coupled amplifier circuit that eliminates transformer induced non-linearities by way of a dual feedback path without sacrificing any of the inherent attributes of general transformer coupled amplifiers.

Abstract: An apparatus for stimulating and controlling the contraction of muscles includes conductive electrodes for contacting spaced-apart locations on the body between which are the muscles to be exercised. The electrodes are connected to a signal supply circuit which includes a pulse generator, a modulator circuit, a push-pull amplifier, a current control circuit and a transformer, the primary winding of which is driven by the amplifier and the secondary winding of which is connected to the electrodes. A second, lower repetition rate, pulse generator can be included to modulate the output so that signals are provided in spaced groups of pulses. The controlled current output is adjustable and monitored by a meter. A counter for counting pulse groups is included.

Abstract: A synchro buffer amplifier is provided which uses two matched amplifiers respectively connected to the primary windings of two transformers. Two input leads are respectively connected to the inputs of the two amplifiers and a third input lead is grounded. The secondary windings of the two transformers are connected in series, and three output leads are respectively connected to the other sides of the two secondary windings and to the common secondary connection. Direct feedback is provided for each amplifier. Any circuit unbalance is compensated by the insertion of a low value choke in the common transformer secondary connection. Three capacitors are connected across the respective output leads partially to tune the loads, and thereby to nullify to some extent the effects of heavy inductive loads so as to allow operation of the buffer amplifier over a wider range of loads than would otherwise be possible.